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Melting Marsilea hirsuta & Staurogyne repens?

Lee Sweeting

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Hi! I have just set up my first planted tank, its been running fine for a month now. Over the last week there has been some melt on the above plants.

My set up.

Juwel Rio 125
2 x 28w T5's (with reflectors)
Pressurised Co2
10 x Tank turn over with a Tetra Tec EX 1200

Initially i was following Setting up a 'higher' tech planted tank | UK Aquatic Plant Society. About 2 weeks in i started to notice some diatoms so i removed the reflectors and reduced the photo period to 6 hrs (the diatoms have now cleared). Now i am starting to get some melt as discussed above. I always thought my Co2 levels were fine, as I had a nice lime green colour in my drop checker. When the melt started, and as I have no fauna in the tank, i increased the Co2 (its a slightly lighter lime green now). I've also been dosing easy carbo at twice the recommended daily dosage since starting the tank. I'm also dosing Tropica specialised at 7.5ml per day, and i'm also using colombo flora base, and ADA power sand.

Basically i just wanted to ask some of the more experienced members if i am thinking along the right track? I don't want to have a complete melt down. I'm still running the lights without the reflectors with a photoperiod of six hours, and i have increased the co2 a fair bit since noticing the melt. I have also added an extra 350 lph power head to increase the flow (just in case).

Any suggestions or advice would be welcomed.

Thanks,

Lee.
 

ceg4048

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Hi Lee,
If you are not at the limit of fish tolerance then you can increase the bubble rate. These are the same old issues with light and CO2. It might be that you need to change the timing of the CO2 so that it comes on earlier. I can't recall if we talked about taking the pH readings throughout the day to see how effective your CO2 injection is. You can maybe even do a large prune to free up space and reduce CO2 demand. I also can't recall if we investigated your distribution and CO2 dissolution methods.

Cheers,
 

Lee Sweeting

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Thanks for the reply Clive, i was hoping you would respond. I don't think we have spoken about Co2 before? I currently have my Co2 coming on 3 hrs before lights on and two hours before lights off, my drop checker is showing a light lime green colour at lights on. I have quite a hard mains water supply though, and my current injection rate is quite heavy. I can't even count the number of bps in my bubble counter. I haven't tested KH myself but my water report is saying that the current supply is 14 degrees. Will this cause me problems? I do have a PH test kit, would it be possible for you to explain how to test how effective my Co2 injection is? I'm a real newbie to the hobby so excuse my ignorance. I have just done a large prune, so as you said that may help?. I'm pretty sure my flow/distribution is good. I have lots of Co2 bubbles all over the tank. I was using Ed's tuorial, and i have my lilly pipes set up as he suggests. In addition i also added a 350 lph power head. I'm getting lots of plant movement all over my tank. My diffuser is placed opposite the out flow of my filter (see picture below), i'm presuming this is what you mean by dissolution method?

Thanks for the help clive, your advice is very much appreciated.

This picture is before i added a power head, and had issues with melt.

HOogQ6Y.jpg
 

Lee Sweeting

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Clive, just a quick note. I've been playing with my Co2 over the last couple of days. Like i said i have my Co2 coming on 3 hrs before lights on and two hours before lights off. I've been watching my drop checker all day. I have a light lime green colour at lights on, and the drop checker is just starting to turn yellow as the Co2 stops, two hours before lights off. So i'm presuming that the water column is fully saturated at this point, and slightly over the required 30 ppm? Am i right in thinking this is what needs to be happening?
 

ceg4048

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Hi Lee,
Well, this may sound contradictory, but you really have to forget about numbers like 30ppm, which are basically meaningless. Did you realize that 90% of the gas you are injecting goes immediately out the window? That's just the nature of gases. They don't really care about you or your plants.Only about 10% of what you inject, and only 10% of what the DC tells you is available actually makes it into the plant beds.

The DC is just a guide. It tells you whether you are on the right track, but do not get hung up on a number like 30ppm, which is really just an arbitrary fantasy number that people more or less agree is a good target indication, kind of like fantasy football. When I think about how much CO2 I need, I never think about 30ppm, instead, I think that I need enough CO2 so that the plants do not suffer CO2 deficiency, and not so much that the fish are endangered. If that means a yellow DC then so be it. If you can get away with a bluer DC then that's fine too. What color you need will depend on all the other factors in the tank such as PAR, flow, distribution, species, as well as location in the tank.

As mentioned in the DC tutorial, it's response is very slow, so we have to abandon all hope of using it to determine instantaneous absolute concentration value. Instead, we take pH readings every hour or even every half hour from just before gas on, to lights on and then to lights off. This progression will show us how the CO2 is being dissolved because the more CO2 is dissolved the more the pH is depressed.

You may also want to experiment with the positioning of your pipe and pump or even with the placement of the diffuser. You can have good luck sometimes porting the gas into the filter intake pipe. There a re lots of ways to skin the cat so you shouldn't be stuck with only the geometry shown in the guide. Try one thing at a time to see what has the best effect.

The KH of the water is not important from this point of view. It just means that the water has high alkalinity and will not change pH with the addition of gas as much as it would if the KH were a lower number.

Take the readings and report back, then we can see if you need to tweak the timing.

Cheers,
 

Lee Sweeting

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Hi Clive! As you suggested i have been taking Ph readings all day . The results are as follows:

11:00 (Co2 On) Ph was 7.0 just before Co2 came on.
12:00
13:00
14:00 (Lights On) Ph was 6.6 just before the lights came on.
15:00 Ph 6.4
16:00 Ph 6.2
17:00 Ph 6.0
18:00 Ph 6.0 (Co2 Off)
19:00 Ph 6.2
20:00 Ph 6.6 (Lights Off)

Hope that all make sense!? I'm very interested to see what the results are saying. There was defiantly a lot of food for thought in your last message. I am aware that the Ph should drop as Co2 is injected. However I’m not sure if i should have the 6.0 Ph reading at lights on? Is this the optimum level for Co2 at lights on, or should it be dropping, as showing, throughout the photoperiod? I'm looking forward to your response.

Thanks again,

Lee.
 

ceg4048

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Hi Lee,
Yeah, those numbers don't look great. If your pre-CO2 is 7.0 and if you are injecting for 3 hours then it is not very good sign to have only dropped the ph by 0.4 units. In 3 hours of injection you should be able to drop the pH by a full unit, which, as you surmise is the general goal. In your case a full 1 unit fall requires the entire photoperiod duration. This explains why the DC is yellow far into the photoperiod.

So this indicates any combination of the following:

The position/location of your diffuser is not good.
The injection rate is insufficient.
The diffuser itself is not efficient.
Flow/distribution are suspect.

It would be easy to increase the injection rate, but then, as you can see, if the injection continues into the photoperiod then you risk toxicity to fauna. If you go that way then you should turn the gas on later and turn it off much earlier than you do now.

As I mentioned, you could change the position of the diffuser so that it is beneath the inlet pipe, so that the filter swallows the gas, mixes it up and spits it out the pipe, or it can be place some other location such as under the outflow pipe near the substrate.

Try making any combination of adjustments and repeat the pH measurements to see which of the adjustments is most (or least) effective. Obviously, the faster you are able to depress the pH, the better.

I'm not really a lily pipe fan, but I won't bash them because many use them successfully.

Make sure you keep the diffuser ceramic disk as clean as possible by soaking in bleach and rinsing thoroughly.

Liquid carbon is a good temporary crutch to use while you try to troubleshoot the cause of poor diffusion, so maybe use some daily at or near lights on to keep the melting from occurring.

Cheers,
 

Lee Sweeting

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Oh Dear, not what i was wanting to hear! Thanks for the info though clive. I'm really not sure what route to go down if i am honest. I thought my flow/distribution was pretty good, but i could be wrong. I do have a spray bar that would run the full length of the back glass. If i was to do that and add an inline diffuser, do you think my dissolution would be improved? I know there are a lot of variables but i just want to give myself the best possible chance at this stage.
 

ceg4048

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Yes, there are a lot of variables, but what you must do is to approach the problem with very tight focus, to be systematic and to change one thing at a time. As I mentioned, the easiest thing to do is to port the gas directly into the filter intake, or at least, find a way to get most of the bubbles into the intake pipe. It looks like you have one of those fancy intake pipes, but you have to abandon style for the moment in order to solve a critical problem. If you have an old school style pipe with an open bottom, just attach it and place the diffuser under the open bottom so that as many bubbles as possible enters the intake. Then take the measurements. If that method is successful then all you need to do is to figure out a way to keep your fancy intake and to still get the gas into it.

The spraybar with inline diffuser generally is the most efficient solution I think, especially from a distribution standpoint, but try that last. See if a simple relocation of the diffuser with an injection rate and timing change can solve the problem.

Cheers,
 

Lee Sweeting

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Ok, thanks Clive. I've moved the diffuser this morning. It is now under the filter intake. Pretty much all of the bubbles from the diffuser are going up the intake and through the filter. I'm getting a nice fine mist coming out of the outflow. I've been taking Ph readings since this morning, so i'll see how things go. I have read that putting Co2 through your filter can be detrimental to it's operation? Do you know if there any truth in this? If the readings return positive values i may invest in an inline diffuser, which as far as i understand, should have a similar effect to placing the diffuser under the filter intake. I'll report on the results later on tonight :). Thanks for all your help clive, i've defiantly learnt a few things about Co2 injection over the last couple of days, and i'm certainly feeling slightly more confident that i can achieve the desired result.

Thanks again,

Lee.
 

ceg4048

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Lee Sweeting

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Haha! Dam matrix ;). On a brighter note, since putting the diffuser under the filter intake, the Ph readings are looking promising :). My Ph readings dropped a whole degree from 7.0 to 6.0, one hour before lights on, and has remained at 6.0 ever since. I've also had a lovely lime green colour in my DC since an hour before lights on. I'm just waiting to see if/when my DC starts to show a yellow colour. Everything going well i think i will change my Co2 on time to two hours before lights on, and change my Co2 off time depending on what my DC tells me later on today. This thread has really opened my eyes to the world of Co2 :D, thanks again Clive.
 

ceg4048

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Welcome to the desert........of The Real.....

Hopefully, the adjustment you made stops the melting. There are other things that can hurt, such as overzealous lighting, poor maintenance and poor flow/distribution. If these items are or have been addressed then there ought to be an improvement.

Gas exchange in aquatic plants is by far the most important feature that determines success. It is more important than PAR or PUR or even nutrients to some extent. It is thousands of times more important than substrate.

When you do a water change, preen the leaves of the plants and wipe off the biofilm and debris that settles on the upper surface of the leaves. Even shake large stems to dislodge the debris. You will see clouds of dirt produced by the plant itself which are waste products siphon this and get it out of the tank. Keep the tank scrupulously clean. If your efforts are successful and if the plants accelerate their growth then this will produce more waste products as a result of their growth. Give the plants every chance for recovery by doing ALL things conducive to maximizing the rate of movement of various gases into and out of the plant. These gases accomplish incredible things because the are constructed of things the plant desperately needs. Chief among these gases is CO2 because it is in part constructed of, and therefore carries, Carbon. 40% or more of a plants dry mass is Carbon. It is the same carbon that burns in your fireplace as logs or coal.

The oldest and largest and heaviest living things on the planet are plants, and much of that mass literally comes in from the thin air where lives the humble gas molecule CO2. In water, CO2 and other gases move 10,000X SLOWER than they do in air, so plants are at a severe disadvantage when flooded.

Because we cannot SEE gases, their importance is easily dismissed, in favor of more sexy things like light, which of course, we can see. But the real deal happens at the interface of the plant outer membrane and the water column. When you look at the plants try conjuring up an image of an astronaut in space wearing a protective a suit , or a deep sea diver with a long air supply line. That's what plants have to deal with, because flooding for a plant is a hostile change of environment. Help them to make the conversion by maximizing movement of gases.

In this photo, looming among a forest of giant crypts rises a lily leaf. Look at the bubbles. Those bubbles are gases inside the plant, not on the exterior. There is are exit points distributed on the leading edge of the leaf. The lighting here is low so the image is dull, but you should be able to clearly see the gases through the membrane.
8398024438_293d933942_c.jpg


Cheers,
 

Lee Sweeting

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Thanks Clive, that all makes good sense, and i will endeavour to do as you have suggested. Hopefully we have overcome my Co2 problem now :) I feel quite relieved after seeing depression of the Ph today. However i did notice that my drop checker had just started to change slightly yellow at Co2 off (the same as yesterday). Is this acceptable? I've recorded the Ph readings from todays experiment. These are as follows:

11:00 (Co2 On) Ph 7.0
12:00 Ph 6.4
13:00 Ph 6.0
14:00 (lights on) Ph 6.0
15:00 Ph 6.0
16:00 Ph 6.0
17:00 Ph 6.0
18:00 (Co2 off) Ph 6.0
19:00 Ph 6.0
20:00 (lights off) Ph 6.4

As a said earlier, my DC was a nice lime green an hour before lights on, and it pretty much stayed that way all day. Just before lights off the DC had a slight yellow tinge to it. Is this normal given the Ph readings shown above?

Thanks,

Lee.
 

ceg4048

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Hi Lee,
Thanks for collecting the additional data. That concentration profile looks ideal to me, and you didn't even have to spend £49.99 at Petsmart, or at [insert favorite boutique aquarium supplier here].

At this point I would totally ignore the behavior of the DC, because, of course, it's just a test kit and that's how test kits behave. The DC is depending on the same phenomenon of carbonic acid production to drop the pH inside the vial. The CO2 must escape the tank water and evaporate into the air space just above the sample water. Temperatures, pressures and so forth affect the ability of the gas to escape into the vial and to then diffuse into the sample water. So this means that gas exchange in water is a problem for dropcheckers too.....Imagine that....and that is why I mention that the DC is just a rough guide. And that's why becoming hypnotized by the 30ppm Holy Grail is such an illusion.

If the DC were blue, for example, and if I had not checked the pH profile to fingerprint the behavior of the gas in that tanks configuration, I would have to pay attention to the DC color and investigate. If it were yellow at lights on and if there were fish in the tank I would need to investigate to see if toxicity was a threat. But now we have a much more accurate idea because we are measuring the difference in acidic content and are not concerned with their absolute values.

Cheers,
 

ceg4048

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Here is the view from topside. The plant is immaculate and is in peak health when gas exchange is maximized.
8395151050_6843e42352_c.jpg


Cheers,
 
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